Rohan’s work focuses on understanding and treating depression in adults. Rohan is especially interested in developing and testing new treatments for depression that prevent recurrence, the return of depression repeatedly over time. Rohan has general expertise in cognitive-behavioral therapy for depression and a subtype of recurrent depression called seasonal affective disorder (SAD), depression in the fall and winter months that improves in the spring. She is best known for her randomized clinical trials comparing cognitive-behavioral therapy and light therapy for SAD.